Implement RADEON_PARAM_SCRATCH_OFFSET getparam.

When this succeeds, userspace can read the scratch register contents from the
mapped writeback page directly.

diff --git a/shared-core/radeon_state.c b/shared-core/radeon_state.c
index 2c169ac..58251dd 100644 (file)
--- a/shared-core/radeon_state.c
+++ b/shared-core/radeon_state.c
@@ -3025,6 +3025,11 @@ static int radeon_cp_getparam(DRM_IOCTL_ARGS)
        case RADEON_PARAM_GART_TEX_HANDLE:
                value = dev_priv->gart_textures_offset;
                break;
+       case RADEON_PARAM_SCRATCH_OFFSET:
+               if (!dev_priv->writeback_works)
+                       return DRM_ERR(EINVAL);
+               value = RADEON_SCRATCH_REG_OFFSET;
+               break;
        
        case RADEON_PARAM_CARD_TYPE:
                if (dev_priv->flags & CHIP_IS_PCIE)